The present disclosure relates to processes for producing pigment dispersions useful in making toner suitable for electrostatographic apparatuses.
Numerous processes are within the purview of those skilled in the art for the preparation of toners. Emulsion aggregation (EA) is one such method.
Typically, the colorants utilized in EA toner processes are in aqueous dispersions in which colorant particles are stabilized by surfactant and dispersed in water. Such colorant dispersions may be made using a high pressure piston-type homogenizer, (e.g., an Ultimaizer) generally yielding dispersions having fine particle size distribution, stabilized, for example, with sodium dodecylbenzene sulfonate surfactant. However, that approach has limitations in capacity and carries a high capital cost. Other methods may include using an in-line rotoristator-type homogenizer which requires less capital investment and maintenance. However, the process can exceed four hours to obtain colorant for making toner.
There remains a need to develop a dispersion technology which reduces processing time and cost, without sacrificing benchmark material properties (e.g., small size and narrow particle size distribution).